Improved mold-board for plows



v 2 SheetsSh'eet 1. SESSiONS & KNOX.

Plow Moldboard.

No. 99,516.' I Patented FebLl, I870.

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N.FETERS, VNOTO-HTMOQRAPHER, WASHINGTON n C 2 Sheets Sheet' 2.

SESSIONS & KNOX.

Plow Moldboard.

No." .99,516. Patented Feb.. I, 1870.

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F. E. SESSIONS AND SAMUEL A. KNOX, OF \VORGESTER, MASSACHUSETTS.

IMPROVED MOLD-BOARD FOR PLOWS.

Specification forming part of Letters Patent No. 99,5!6, dated February 1, ISO.

' To all whom it may concern,

Be it known that we, F. E. SESSIONS and S. A. KNOX, of the city and county of W'orcester,and Commonwealth of Massachusetts,

full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this specification,

in which Figure 1 represents a side view of our improved mold-board. Fig. 2 represents, upon an enlarged scale, a section on line A B, Fig. 1; and Fig. 3 represents a longitudinal vertical section of a set of dies used in the process of manufacturing our improved mold-board.

To enable those skilled in the art to which our invention belongs to make and use the same, we will proceed to describe it more in detail. i 1

The nature of our invention consists in an improved mold-board for plows, made substantially in the manner and by .the process hereinafter explained.

In the drawings, A represents one of our improved mold-boards, which, in its outward form, does not differ materially from those in common use prior to our said invention.

It has been the great aim of plow-manufacturers to produce a mold-board which should present an outer surface of great hardness, while at the same time avoiding the objections to the use of a mold-board so brittle as to be liable to break by sudden concussions. In furtherance of such designs, three principal plans have been adopted, one of which consists in the use of three-ply stock, as it is called, made by welding a sheet of steel upon each side of a sheet of iron. From stock or material thus made mold-boards have been out out and fashioned. Objections of a Very serious nature are met with, however, in carrying out the manufacture. In the first place, the expense of manufacturing the threeply stock increases the cost of the mold-boards to such an extent as to almost preclude the adoption of the plan, if no other objection existed. Practical tests, however, have proved that no reliance can be placed upon securing a perfect weld,which is another serious objection to the adoption and use of the three-ply stock. Another plan, which has been adopted and used to a considerable extent, consists in making the mold-boards of cast cast-steel. To insure the proper strength, however, the mold-boards have to be cast thick, thus making them heavy, while at the same time they are constantly lia ble to break by sudden concussions. Still another plan adopted is that for which Letters Patent were granted to us on the 2ith day of March, 1868, N 0. 75,986, as the assignees of said Sessions, and which consists in'immersing the mold-board of the iron or steel in molten cast-iron after it has been shaped as stated in said patent.

In the hands of careful and experienced workmen, mold-boards can be made in this way which good judges have pronounced to be superior to any made by the various other processes practiced prior to our present inven tion. In the hands of careless or inexperienced workmen,.however, the mold-boards made by the last-named process are liable to be defective. since, if the mold-board is allowed toremain in the molten cast-iron too long, the mold board becomes carbonized entirely through, and is then liable to break like a piece of cast or hardened steel.

To obviate the objections to all the plans above named, while at the same time securing the advantages incident to each of them, has been our object in' making the experiments which have led to our present invention. In the first place we commence with the manufacture of the iron plate into steel, and arrest the process after the plate has been subjected to the carbonizing operation long enough to convert, say, about one-third of the thickness on each side of the plate into steel. Stock thus prepared possesses all the essential ele ments of three-ply stock-via, a steel coating with an iron center, while at the same time it is a solid mass. After the blank mold-boards have been cut out of plates thus made, they are drilled with the required holes a a, for securing them in place on the plow, when the mold-boards are placed in a proper furnace and heated to a cherry-red, or nearly so, after which they are taken and placed upon the die B, which is grooved over the surface on which the blank mold-board is laid, as in dicated in Fig. 3, when the upper die, 0, is caused to descend, by proper machinery, upon the mold-board, thereby pressing the latter down upon the lower die and into such a I Ah V j shape that, when the mold is removed, it will be in the shape desired. As soon as the upper die has descended to its lowest point,water is turned into the dish part D of the die 0, which runs through holes b in the bottom F thereof, and thence flows over the top of the mold-board through communicating grooves c in the bottom of the die 0. The top of the lower die, B, is also cut out with communicating grooves cl, into which the water flows as it runs over the outer edges of the moldboard. Some water also flows through the holes a. The upper die is perforated with holes as thick consistent with due regard to strength. The holes b may be made in regular or irregular rows, as indicated in Fig; 3.

We have here described the construction of dies which we prefer; but it is evident that tion.

The water, also, may be introducedin other ways, and by the use of instrumentalities differing from the particular one herein shown and described.

From the foregoing description it will be seen that .the mold-board is held firmly between the dies B and 0 until after the application of the water, as explained above.

We have found, in order to obtain a plane surface upon any particular line running from the edge e to the edge 7, that it is necessary to concave the lower die somewhat, the upper die being made with a corresponding convexity, as illustrated in Fig. 3. The necessary degree of concavity and convexity of the dies will depend upon the particular shape and size of the mold-boards.

A cross-section of our improved mold-board is shown upon an enlarged scale in Fig. 2 of the drawings, in which the parts marked 1 l are the steel outsides, while the part marked 2 is the iron center.

One great advantage resulting from our present invention is that the mold-boards can be made by unskilled and ordinary workmen, since overheating of the blank mold-boards before they are placed between the dies does not injure them materially, the malleable or iron center remaining, notwithstanding such overheating.

The employment of the dies in the manner specified insures accurate work,'while the application of thewater to nearly the entire surface of the top and bottom of the mold-board while it is held between the dies prevents twisting and springing thereof during the operation of cooling and hardening the moldboard.

Having described our improvements in mold-boards for plows, what we claim therein as new and of our invention, and'desire to secure by Letters Patent, as an improved article of manufacture, is

A metallic mold-board for plows, made by the process and in the manner substantially as above described.

F. E. SESSIONS. SAMUEL A. KNOX. \Vit-nesses:

THOS. H. Doncn, A. E. PEIRCE. 

